Technical Field
The present disclosure relates to a lock-up device, and particularly to a lock-up device for a torque converter, which is configured to transmit a torque from a front cover to a transmission-side member through a turbine.
Background Information
Torque converters are often equipped with a lock-up device for directly transmitting a torque from a front cover to a turbine. Such a lock-up device includes a piston, an input-side plate, a plurality of torsion springs, and an output-side plate. The piston is capable of being coupled by friction to the front cover. The input-side plate is fixed to the piston. The torsion springs are supported by the input-side plate. The output-side plate is elastically coupled through the torsion springs to the piston and the input-side plate in a rotational direction. The output-side plate is fixed to the turbine.
Additionally, as described in Japan Laid-open Patent Application Publication No. 2012-237441, there has been also proposed a type of lock-up device that a plurality of clutch plates are used to increase its clutch capacity. In the lock-up device described in Japan Laid-open Patent Application Publication No. 2012-237441, the plurality of clutch plates are disposed between a clutch input member fixed to the front cover and a clutch output member fixed to a member composing a damper portion.
In the lock-up device described in Japan Laid-open Patent Application Publication No. 2012-237441, the clutch output member, fixed to the member composing the damper portion, is required to be disposed on the output side of the plurality of clutch plates. The requirement of the clutch output member results in increase in number of components and enlargement in axial space.